rf24-pio/examples/starping_relay/starping_relay.pde

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/*
Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.
*/
/**
* Example RF Radio Ping Star Group with Relay
*
* This sketch is a more complex example of using the RF24 library for Arduino.
* Deploy this on up to six nodes. Set one as the 'pong receiver' by tying the
* role_pin low, and the others will be 'ping transmit' units. The ping units
* unit will send out the value of millis() once a second. The pong unit will
* respond back with a copy of the value. Each ping unit can get that response
* back, and determine how long the whole cycle took.
*
* This example introduces a new role, the 'relay', which can relay pings or
* pongs from one host to another. This is needed in larger meshes because
* each radio can only listen to 5-6 others.
*
* This example requires a bit more complexity to determine which unit is which.
* The pong receiver is identified by having its role_pin tied to ground.
* The ping senders are further differentiated by a byte in eeprom.
*/
#include <SPI.h>
#include <EEPROM.h>
#include "nRF24L01.h"
#include "RF24.h"
#include "printf.h"
//
// Hardware configuration
//
// Set up nRF24L01 radio on SPI bus plus pins 8 & 9
RF24 radio(8,9);
//
// Topology
//
// Radio pipe addresses for the nodes to communicate. Only ping nodes need
// dedicated pipes in this topology. Each ping node has a talking pipe
// that it will ping into, and a listening pipe that it will listen for
// the pong. The pong node listens on all the ping node talking pipes
// and sends the pong back on the sending node's specific listening pipe.
struct node_info
{
uint64_t talking_pipe; // Pipe used to talk to parent node
uint64_t listening_pipe; // Pipe used to listen to parent node
uint8_t parent_node; // Number of parent node
};
const node_info topology[] =
{
{ 0x0000000000LL, 0x0000000000LL,-1 }, // Base
{ 0xF0F0F0F0E1LL, 0x3A3A3A3AE1LL, 0 }, // Relay
{ 0xF0F0F0F0D2LL, 0x3A3A3A3AD2LL, 1 }, // Leaf
{ 0xF0F0F0F0C3LL, 0x3A3A3A3AC3LL, 1 }, // Leaf
{ 0xF0F0F0F0B4LL, 0x3A3A3A3AB4LL, 1 }, // Leaf
{ 0xF0F0F0F0A5LL, 0x3A3A3A3AA5LL, 0 }, // Leaf, direct to Base
};
const short num_nodes = sizeof(topology)/sizeof(node_info);
/**
* Find where to send a message to reach the target node
*
* Given the @p target_node, find the child or parent of
* the @p current_node which will relay messages for the target.
*
* This is needed in a multi-hop system where the @p current_node
* is not adjacent to the @p target_node in the topology
*/
uint8_t find_node( uint8_t current_node, uint8_t target_node )
{
uint8_t out_node = target_node;
bool found_target = false;
while ( ! found_target )
{
if ( topology[out_node].parent_node == current_node )
{
found_target = true;
}
else
{
out_node = topology[out_node].parent_node;
// If we've made it all the way back to the base without finding
// common lineage with the to_node, we will just send it to our parent
if ( out_node == 0 || out_node == -1 )
{
out_node = topology[current_node].parent_node;
found_target = true;
}
}
}
return out_node;
}
//
// Role management
//
// Set up role. This sketch uses the same software for all the nodes
// in this system. Doing so greatly simplifies testing. The hardware itself specifies
// which node it is.
//
// This is done through the role_pin
//
// The various roles supported by this sketch
typedef enum { role_invalid = 0, role_base, role_relay, role_leaf } role_e;
// The debug-friendly names of those roles
const char* role_friendly_name[] = { "invalid", "Base", "Relay", "Leaf" };
// The role of the current running sketch
role_e role;
//
// Address management
//
// Where in EEPROM is the address stored?
const uint8_t address_at_eeprom_location = 0;
// What flag value is stored there so we know the value is valid?
const uint8_t valid_eeprom_flag = 0xdf;
// What is our address (SRAM cache of the address from EEPROM)
// This is an index into the topology[] table above
uint8_t node_address = role_invalid;;
//
// Payload
//
struct payload_t
{
uint8_t from_node;
uint8_t to_node;
uint16_t id;
unsigned long time;
static uint16_t next_id;
payload_t(void) {}
payload_t(uint8_t _from, uint8_t _to, const unsigned long& _time): from_node(_from), to_node(_to), id(next_id++), time(_time) {}
};
uint16_t payload_t::next_id;
void payload_printf(const char* name, const payload_t& pl)
{
printf("%s Payload from:%u to:%u id:%u time:%lu",name,pl.from_node,pl.to_node,pl.id,pl.time);
}
//
// Setup/loop shared statics
//
static unsigned long last_ping_sent_at;
static bool waiting_for_pong = false;
static short consecutive_timeouts;
const unsigned long ping_delay = 2000; // ms
const unsigned long pong_timeout = 250; // ms
const unsigned long ping_phase_shift = 100; // ms
const short timeout_shift_threshold = 3;
void setup(void)
{
//
// Address
//
// Unless we find reasonable values in the EEPROM, these are the defaults
node_address = -1;
// Look for the token in EEPROM to indicate the following value is
// a validly set node address
if ( EEPROM.read(address_at_eeprom_location) == valid_eeprom_flag )
{
// Read the address from EEPROM
uint8_t reading = EEPROM.read(address_at_eeprom_location+1);
// If it is in a valid range for node addresses, it is our
// address.
if ( reading <= 5 )
node_address = reading;
}
//
// Role
//
// Role is determined by address.
if ( node_address != -1 )
{
// Node #0 is the base, by definition
if ( node_address == 0 )
role = role_base;
else
{
// Otherwise, it is probably a leaf node
role = role_leaf;
// If there are any nodes in the topology table which consider this
// a parent, then we are a relay.
int i = num_nodes;
while (i--)
{
if ( topology[i].parent_node == node_address )
{
role = role_relay;
break;
}
}
}
}
//
// Print preamble
//
Serial.begin(9600);
printf_begin();
printf("\n\rRF24/examples/starping_relay/\n\r");
printf("ROLE: %s\n\r",role_friendly_name[role]);
printf("ADDRESS: %i\n\r",node_address);
//
// Setup and configure rf radio
//
radio.begin();
//
// Open pipes to other nodes for communication
//
// Each leaf node has a talking pipe that it will ping into, and a listening
// pipe that it will listen for the pong. Relay nodes also do this.
if ( role == role_leaf || role == role_relay )
{
// Write on our talking pipe
radio.openWritingPipe(topology[node_address].talking_pipe);
// Listen on our listening pipe
radio.openReadingPipe(1,topology[node_address].listening_pipe);
}
// Relay nodes have a special function. They open their listening pipe on pipe
// #0. This will get over-written every time we open a writing pipe. So
// Remember to re-open the reading pipe whenever we start to listen again.
if ( role == role_relay )
{
// Listen on our listening pipe
radio.openReadingPipe(0,topology[node_address].listening_pipe);
}
// The base and relay nodes listens on all their children node's talking pipes
// and sends the pong back on the child node's specific listening pipe.
if ( role == role_base || role == role_relay )
{
// First child listening pipe is #1
uint8_t current_pipe = 1;
// The topology table tells us who our children are
int i = num_nodes;
while (i--)
{
if ( topology[i].parent_node == node_address )
radio.openReadingPipe(current_pipe++,topology[i].talking_pipe);
}
}
//
// Start listening
//
radio.startListening();
//
// Dump the configuration of the rf unit for debugging
//
radio.printDetails();
//
// Prompt the user to assign a node address if we don't have one
//
if ( role == role_invalid )
{
printf("\n\r*** NO NODE ADDRESS ASSIGNED *** Send 0 through 5 to assign an address\n\r");
}
}
void loop(void)
{
//
// Leaf role. Repeatedly send the current time
//
if ( role == role_leaf )
{
// Is it time to ping again?
unsigned long now = millis();
if ( now - last_ping_sent_at >= ping_delay )
{
last_ping_sent_at = now;
waiting_for_pong = true;
// First, stop listening so we can talk.
radio.stopListening();
// Take the time, and send it to the base. This will block until complete
payload_t ping(node_address,0,millis());
// Print details.
printf("%lu ",millis());
payload_printf(">PING",ping);
bool ok = radio.write( &ping, sizeof(payload_t) );
if (ok)
printf(" ok\n\r");
else
printf(" failed\n\r");
// Now, continue listening
radio.startListening();
}
// Did we get a pong?
if ( radio.available() )
{
// Not waiting anymore, got one.
waiting_for_pong = false;
consecutive_timeouts = 0;
// Dump the payloads until we've gotten everything
payload_t payload;
boolean done = false;
while (!done)
{
// Fetch the payload, and see if this was the last one.
done = radio.read( &payload, sizeof(payload_t) );
// Print details.
printf("%lu ",millis());
payload_printf(">PONG",payload);
printf(" Round-trip delay: %lu\n\r",millis()-payload.time);
}
}
// Have we timed out waiting for our pong?
if ( waiting_for_pong && ( millis() - last_ping_sent_at > pong_timeout ) )
{
// Not waiting anymore, timed out.
waiting_for_pong = false;
// Timeouts usually happen because of collisions with other nodes
// getting a pong just as we are trying to get a ping. The best thing
// to do right now is offset our ping timing to search for a slot
// that's not occupied.
//
// Only do this after getting a few timeouts, so we aren't always skittishly
// moving around the cycle.
if ( ++consecutive_timeouts > timeout_shift_threshold )
last_ping_sent_at += ping_phase_shift;
// Print details
printf("TIMED OUT.\n\r");
}
}
//
// Relay role. Forward packets to the appropriate destination
//
if ( role == role_relay )
{
#if 1
// Relay role is ALSO a ping sender!!
// Is it time to ping again?
unsigned long now = millis();
if ( now - last_ping_sent_at >= ping_delay )
{
last_ping_sent_at = now;
// First, stop listening so we can talk.
radio.stopListening();
// Write on our talking pipe. The relay has to do this every time, because
// we ALSO use pipe 0 as a listening pipe.
radio.openWritingPipe(topology[node_address].talking_pipe);
// Take the time, and send it to the base. This will block until complete
payload_t ping(node_address,0,millis());
printf("%lu ",millis());
payload_printf(">PING",ping);
bool ok = radio.write( &ping, sizeof(payload_t) );
if (ok)
printf(" ok.\n\r");
else
printf(" failed.\n\r");
// Now, continue listening
radio.openReadingPipe(0,topology[node_address].listening_pipe);
radio.startListening();
}
#endif
// if there is data ready
uint8_t pipe_num;
if ( radio.available(&pipe_num) )
{
// Dump the payloads until we've gotten everything
payload_t payload;
boolean done = false;
while (!done)
{
// Fetch the payload, and see if this was the last one.
done = radio.read( &payload, sizeof(payload_t) );
// Is this for us?
if ( payload.to_node == node_address )
{
// Treat it as a PONG
printf("%lu ",millis());
payload_printf(">PONG",payload);
printf(" Round-trip delay: %lu\n\r",millis()-payload.time);
}
else
{
// Relay it
// Spew it
printf("%lu ",millis());
payload_printf("RELAY",payload);
printf(" on pipe %u. ",pipe_num);
// Which pipe should we use to get the message to the "to_node"?
// We need to find a node who is OUR CHILD that either IS the to_node
// or has the to_node as one of ITS children. Failing that, we'll just
// send it back to the parent to deal with.
uint8_t out_node = find_node(node_address,payload.to_node);
// First, stop listening so we can talk
radio.stopListening();
// If this node is our child, we talk on it's listening pipe.
uint64_t out_pipe;
if ( topology[out_node].parent_node == node_address )
out_pipe = topology[out_node].listening_pipe;
// Otherwise, it's our parent so we talk on OUR talking pipe
else
out_pipe = topology[node_address].talking_pipe;
// Open the correct pipe for writing.
radio.openWritingPipe(out_pipe);
// Send the payload back out
bool ok = radio.write( &payload, sizeof(payload_t) );
// Debug spew
uint16_t pipe_id = out_pipe & 0xffff;
printf("OUT on pipe %04x %s.\n\r",pipe_id,ok?"ok":"failed");
}
}
// Now, resume listening so we catch the next packets.
radio.openReadingPipe(0,topology[node_address].listening_pipe);
radio.startListening();
}
}
//
// Base role. Receive each packet, dump it out, and send it back
//
if ( role == role_base )
{
// if there is data ready
uint8_t pipe_num;
if ( radio.available(&pipe_num) )
{
// Dump the payloads until we've gotten everything
payload_t ping;
boolean done = false;
while (!done)
{
// Fetch the payload, and see if this was the last one.
done = radio.read( &ping, sizeof(payload_t) );
// Spew it
printf("%lu ",millis());
payload_printf("PING",ping);
printf(" on pipe %u. ",pipe_num);
}
// First, stop listening so we can talk
radio.stopListening();
// Construct the return payload (pong)
payload_t pong(node_address,ping.from_node,ping.time);
// Find the correct pipe for writing. We can only talk on one of our
// direct children's listening pipes. If the to_node is further out,
// it will get relayed.
uint8_t out_node = find_node(node_address,pong.to_node);
// Open the correct pipe for writing
radio.openWritingPipe(topology[out_node].listening_pipe);
// Retain the low 2 bytes to identify the pipe for the spew
uint16_t pipe_id = topology[out_node].listening_pipe & 0xffff;
// Send the final one back.
bool ok = radio.write( &pong, sizeof(payload_t) );
payload_printf(" ...PONG",pong);
printf(" on pipe %04x %s.\n\r",pipe_id,ok?"ok":"failed");
// Now, resume listening so we catch the next packets.
radio.startListening();
}
}
//
// Listen for serial input, which is how we set the address
//
if (Serial.available())
{
// If the character on serial input is in a valid range...
char c = Serial.read();
if ( c >= '0' && c <= '5' )
{
// It is our address
EEPROM.write(address_at_eeprom_location,valid_eeprom_flag);
EEPROM.write(address_at_eeprom_location+1,c-'0');
// And we are done right now (no easy way to soft reset)
printf("\n\rManually reset address to: %c\n\rPress RESET to continue!",c);
while(1);
}
}
}
// vim:ai:cin:sts=2 sw=2 ft=cpp